Cities bag Bloomberg funding for biochar as private sector bets on man-made carbon capture technologies

Bloomberg Philanthropies has announced a multi-million-dollar allocation of funding to seven global cities for the adoption of carbon-capturing biochar, in the same week that major milestones were marked for man-made carbon-sucking projects backed by private sector players like Alphabet and Stripe.

Cities bag Bloomberg funding for biochar as private sector bets on man-made carbon capture technologies

Biochar (pictured) can be added to soils to boost carbon sequestration

Bloomberg Philanthropies will provide up to $400,000 to each of the chosen seven cities so they can bring biochar production facilities online, following the model used at Stockholm’s Biochar Project. The facility in Stockholm has the capacity to produce 100 tonnes of the material annually, having scaled partly due to the support of Bloomberg Philanthropies since 2014. It is hoped that, collectively, production capacity across the supported projects will exceed 3,750 tonnes per year.

Biochar is made by taking plant waste and heating it in either a low or zero oxygen environment. This process leaves behind a “carbon skeleton” which can be used as a soil fertilizer. When used this way, it improves the soil’s ability to sequester carbon, acting as a natural carbon capture solution. Benefits vary depending on location, crop type and other contextual factors.

While biochar seems like a promising climate solution, it remains expensive as global production capacity is still fairly low. A global average price of €1,750 per tonne was recorded in 2020.

The seven cities selected by Bloomberg Philanthropies to receive funding are Darmstadt, Germany; Helsingborg, Sweden; Sandnes, Norway; Helsinki, Finland; Cincinnati, Ohio; Lincoln, Nebraska; and Minneapolis, Minnesota. Helsingborg and Sandnes already host biochar production and will be supported to scale up, while the other five cities will create their first production units.

In each location, plant-based waste will be used as the feedstock for making biochar. Using raw forest materials or crops that could be used for food present sustainability challenges across the biochar value chain, undermining its positioning as a climate solution.

“It is exciting to see the urban biochar community continue to expand,” said Stockholm Mayor Anna König Jerlmyr. “I’m amazed at cities’ ability to continuously develop new biochar systems, production methods and applications. Biochar’s ability to sequester carbon is an important piece of the puzzle to fight climate change, and used in soil biochar makes for greener, more verdant cities.

“In Stockholm, Biochar has become an important part of the City’s Climate Action Plan.”

Readers keen to learn more about Stockholm’s climate response are invited to read edie’s recent explainer published to mark the Stockholm +50 climate conference, contributed by Swedish sustainable development expert Kaj Embrén and environmental activist Charles Secrett.

A mammoth undertaking

The news from Bloomberg Philanthropies comes during what is shaping up to be a busy week for private sector announcements on carbon capture using man-made technologies.

Direct air capture firm Climeworks this week used its annual conference to announce that work has started to develop its largest facility. Called Mammoth and located in Hellisheiði, Iceland, the plant should capture at least two megatonnes of co2 annually by 2030 and Climeworks is aiming for a gigatonne of capture capacity by 2050.


Climeworks’ technology works by drawing air into a collector with a fan. Inside the collector, CO2 is filtered out. When the filter is full, the collector is closed and heated to release the CO2, ready for concentration and storage by storage partner Carbfix. The carbon associated with developing and operating the DAC facilities, Climeworks claims, is typically equivalent to 10% of the carbon that will be captured. This calculation considers the fact that the facilities are powered by renewable energy.

The technology is in operation at 17 other Climeworks plants already, one of which – Orca – is operating commercially. Orca came online in September 2021 and is based in the same Icelandic region. Companies supporting Orca include Microsoft, Swiss Re, Ocado, Square and Boston Consulting Group.

Mammoth is expected to begin operating in either late 2023 or early 2024. In the first instance, it will have a CO2 capture capacity of 36,000 tonnes per year.

Climeworks’ chief executive Christoph Gebald said: “Based on most successful scale-up curves, reaching gigaton by 2050 means delivering at multi-megaton scale by 2030. Nobody has ever built what we are building in DAC, and we are both humble and realistic that the most certain way to be successful is to run the technology in the real world as fast as possible.”

Some climate scientists have concluded that large-scale carbon capture – whether man-made or nature-based – is needed at scale to avert the worst physical impacts of climate change due to historic and continuing emissions. However, man-made systems are in their relative infancy commercially. Critics are concerned that they may not deliver their promised benefits and could be used as a means for businesses to avoid reducing their emissions in the first instance. To date, fewer than 10,000 tonnes ofCO2 have been removed from the air using man-made tech.

A new frontier

In other news from the private sector this week, the Frontier initiative has announced new backing for six projects developing early-stage carbon removal technologies. The initiative, spearheaded by Stripe, launched in April with the support of McKinsey & Company, Meta (formerly known as Facebook), Shopify, and Google’s parent company Alphabet. Inc. Collectively, members have agreed to purchase $925m of carbon removals generated using man-made technologies this decade. Showing demand for removals, it is hoped, will help scale their creation and thus bring down their costs.

The six start-ups being supported by Frontier are AspiraDAC, Calcite-Origen, Lithos Carbon, RepAir, Travertine, and Living Carbon. For all six projects, Stripe has agreed to be the first commercial customer. It has committed $2.4m to purchase carbon removals and a further $5.4m if the projects can reach agreed technical milestones.

“The majority of Frontier’s $925m will go on multiyear offtake agreements designed to help companies scale up their technologies -but while the field is so nascent, we need to keep up momentum on pre-purchases like these to get more companies to the starting line,” said Stripe’s head of climate Nan Ransohoff.

Ransohoff noted that, in the 26 applications Stripe received for support under this workstream, there were a number of common technologies. These included DAC. As well as plants with fans like Climeworks’, DAC applications are being developed in fields like electrochemical capture and metal-organic framework (MOF) absorption. Other common approaches to carbon capture include biomass burial and direct ocean capture.

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